Apparatus for blooming filter tow



Nov. 1, 1966 J. F. CAIN ES ETAL APPARATUS FOR BLOOMING FILTER TOW 2Sheets-Sheet 1 Filed Sept. 26, 1962 m a o liq. v

JAMES E CAM/ES RICHARD H DYE/P JAMES KNOX PA/VN/LL JR.

v INVENTORS ,W M

ATTORNEYS Nov. 1, 1966 J. F. CAINES ETAL 3,282,753

APPARATUS FOR BLOOMING FILTER TOW 2 Sheets-Sheet 2 Filed Sept. 26, 1962JAMES F CA INES R/CHARD F DYE/P JAMES KNOX PAN/V/LL JR.

1N ENT RS ATTORNEYS United States Patent 3,282,768 APPARATUS FORBLOOMING FILTER TOW James F. Caines, Richard F. Dyer, and James KnoxPannill, Jr., Kingsport, Tenn, assignors to Eastman Kodak Company,Rochester, N.Y., a corporation of New York Filed Sept. 26, 1962, Ser.No. 226,432 9 Claims. (Cl. 156-441) This invention relates to newapparatus for processing tow into rod-like elements. More particularly,this invention concerns apparatus of the class indicated wherein tow maybe manufactured into tobacco smoke filter elements of a high qualitywith fewer steps and with less apparatus than heretofore required.

This application is a continuation-in-part of our parent applicationSerial No. 27,091, now US. Patent No. 3,099,594.

The manufacture of tobacco smoke filter elements from special towscomposed of filaments generally in accordance with the disclosure ofCrawford and Stevens US. Patent No. 2,794,480 is already quiteextensively carried out in the industry. In such processes the tow isusually opened up or banded by steps involving primarily mechanicaltreatment.

In a more recent disclosure of Dyer (one of the inventors herein) etal., Serial No. 736,900, now US. Patent No. 3,079,663, there has beendescribed a slot jet con struction and associatedparts whereby existinginstallations in accordance with the aforesaid Crawford and Stevensinventions may be conveniently modified. That is, the said Dyer et al.invention of application Serial No. 736,900 is useful in connection withalready existing installations for suitably modifying such installationsto more efliciently and better handle tow. Also, such type modificationwith a slot jet permits the processing of tow of a wider denier range.

Although the foregoing processes and constructions satisfactorilyfulfill the needs of many manufacturing installations, with the adventof the need of additional installations as well as the desirability ofthe greater facility for processing certain of the tow now available, ademand has arisen for further simplified and improved processes andapparatus as discussed in further detail in parent application SerialNo. 27,091 aforesaid. It is apparent, therefore, that the development ofnew and simplified apparatus for the production of the rod-like elementsuseful for tobacco smoke filter elements represents a highly desirableresult.

After extended investigation we have found apparatus for making elementsof the class indicated and of a quality at least equivalent or incertain instances better than the presently produced elements, butwherein there is substantial apparatus saving in making theconstructions needed for carrying out the instant process.

This invention has for one object to provide a novel and simplifiedapparatus for the manufacture of filter elements and the like rod-likeproduct. Another object is to provide a simplified apparatus combinationfor converting tow to rod-like elements which is adaptable to theprocessing of a wide range of tow deniers. Still a further object is toprovide special jet device construction specially suitable forprocessing tow which is being converted to filter elements. Anotherobject is to provide such jet construction equipped with facilities forthe introduction of addenda into contact with the tow and to prevent theescape thereof in the exhaust from the jet. A limited object is toprovide a jet device construction wherein the entrance end of the jet isprovided with a threaded section adapted to receive means to reduceentrance diameter of the yarn entrance. A further object is to provide ajet having a certain flexible finger construction on the exit end of thejet. Other objects will appear hereinafter.

For assistance in a better understanding of the present inventionreference is made to the attached drawings forming a part of the instantapplication.

FIG. 1 is a semidiagrammatic side elevation view of an apparatuscombination using the apparatus parts of the present invention such asmay be used for manufacturing rod-like elements.

FIG. 2 is a cross-sectional view of a circular jet device such as may beused in the present invention.

FIG. 3 is a detailed side elevation view in section illustrating amodification of the jet inlet end whereby the inlet or entrance is ofsmaller diameter than the tube portion said inlet discharges into.

FIG. 4 is a side elevation view of a jet construction as in FIG. 2 butwherein the jet has been provided with additional parts for facilitatingthe introduction of addenda.

FIG. 5 is a side elevation view somewhat similar to FIG. 4 but whereinthe jet is shown in section for better illustrating wherein the addendaadding conduits and the like parts may be associated with the jet.

FIG. 6 is a side elevation view somewhat of a schematic nature forillustrating the combination of addenda applying apparatus parts inassociation with the circular jet of the instant invention.

Referring now to FIG. 1, the utility of the apparatus of the presentinvention is illustrated as follows: A continuous multifilament crimpedtow 1 is withdrawn from supply package 2 over guide 3 by feed roll pair4. It passes, under tension generated by the suction of jet 6 of thepresent invention over suitable addenda applicator(s) 5 into said jet 6.Here it is subjected to an explosive expansion of compressed air in aspecially adapted nozzle described in more detail hereinafter. While inthe jet, the tow as it is bloomed is subjected by means hereinafterdescribed to a spray or fog of an atomized, liquid, as for example aplasticizer for the tow being processed. The plasticized tow is expelledfrom the jet under the influence of the expanding air flow and passes tofeed rolls 7. Feed roll pair 7 is operated at a somewhat slower speedthan roll pair 4 so that the tow is in a state of relaxation or underthe very minimum of tension between jet 6 and roll pair 7. The tow thenadvances to a stuffing jet 8 as described in Wexler US. Patent 3,016,945or as in Crawford and Stevens US. Patent 2,794,480 and then to acigaretting machine 9.

Referring to FIG. 2, the basic circular jet will now be described. Itwill be noted that the jet is of the same general design andconfiguration as the jets described in Dyer U. S. Patent 2,924,868.However, differences reside in the provision of multiple air inlets tothe jet body and a major revision of the venturi tube structure. Studyhas shown that efficient jets from the viewpoint of minimum energylosses have a relatively small ratio of throat length to throatdiameter. However, it has been found that jets of conventional designare not effective in blooming and debundlizing continuous multifilamenttow containing several thousand highly crimped filaments in the order of0.6 to 16 denier per filament. It was found in certain instances thatthe effective blooming was obtained when the throat length to diameterratio was increased to a ratio of about 6 to 1. For the presentinvention, the exit flare or diverging portion of lt'he nozzle shouldhave an included angle of about 3 to 5 degrees. Thus, the tube design isof some importance to obtain optimum tow blooming and completedebundlizing or separation of the individual filaments fromeach other.

Referring further to FIG. 2, the jet device is comprised of an outsideshell 10 containing several inner members 11,

13 and 14 held in place by threaded plugs 12 and 15. A passageway 16extends through the jet device so that the continuous multifilamentcrimped tow may be passed from the threaded entrance 17 in member 11 toan exit 18 in member 14. Member 17 is threaded so that, for example, aceramic yarn inlet eyelet may be attached of the type to be discussed inconnection with FIG. 3. Or, another entrance assembly as shown in FIG. 3may be screwed in in place of 12. The passageway in member 11 issubstantially of uniform diameter. However, as apparent, if an inleteyelet is used as just mentioned, the entrance diameter is reduced. Theouter surface 19 of the lower end of member 11 is conical in shape withan included angle of about 40 to 80 degrees, for providing, inconjunction with the tapered surface 20 of thin plate orifice plate 13,an annular orifice or passageway for metering the air fiow into the exittube member 14.

The exit tu'be member 14- is provided with a converging entrance section21 of about 30 to 40 degrees included angle, and in series a straightcylindrical tube passage 22 having a length of from 2 to 10 times theinside diameter of the passage 22, and a flaring or diverging exitsection 23 with an included angle of from 2 to 7 angle. Good resultshave been obtained when the length of passageway 22 is about six timesits inside diameter and the included angle of the exit passage 23isabout 3 to degrees.

In addition, it is usually preferred that the inside diameter ofpassageway 22 should be about 0.75" for a tow of about 37,000 deniersize, and should be about 163% of the diameter of the orifice plateorifice 20 and 400% of the inside diameter of the passageway 16 in inlettube 11. The taper 19 of tube 11 should be about 60 degrees and about 30degrees less than the angle of the taper of the orifice 20 in plate 13which should be about 90 degrees. Proper sizing of these items insuresthat the jet will produce a suction at entrance 17 to facilitatethreading the tow into the jet device. They also insure metering andimpingement of the air onto the tow as it enters the orifice plate. Itis also usually desirable that the passageways in the jet be in accurateconcentric and axial alignment to insure uniform impingement of the airon the tow around the periphery of the tow and to insure a minimum ofturbulence and swirling or twisting of the air flow. If the air flowswirls, it will tend to twist the tow, thus compacting it rather thanblooming it and separating the filaments from each other.

Air is provided to the jet shell through one or more openings 24 and 24'to an annular chamber formed by the outer surface of inlet member 11 andshell 10 and sealed at one end by threaded plug 12. It has been foundthat, while one inlet 24 is often adequate, better air flow distributioncan be obtained with two or more openings equi-spaced around the shellperiphery. The air from the chamber 25 then impinges on the tow bypassing through the annular orifice formed by the tapered portion 19 ofinlet tube 11 and the tapered opening 20 in orifice plate 13.

Relationships for a typical preferred jet .for processing 37,000 totaldenier, 1.6 denier per filament tow are given in the following Table A:

TABLE A Inside diameter of tube 11 0.250" Angle of taper 19 on end oftube 11 60 Orifice plate opening diameter 0.468" Orifice plate entranceangle 20 90 Orifice plate thickness 0.125" Venturi tube entrance angle21 35 Venturi tube throat diameter 22 0.750" Venturi tube throat length22 4.50 Venturi tube exit angle 23 5 It has been further found as animportant apparatus feature of the present invention that the bloomingof the tow can be materially enhanced if the flow of. the tow as itexited from the jet exit member 14 is retarded and partially confined.To achieve this end, a plurality of spring fingers 26, 26', 26" andothers (not shown) are positioned about equidistant around the outersurface of the exit member 14 and extend beyond the end of the member 14a distance of 3" to 8". The fingens 26 are curled slightly outward at 27to avoid snagging the tow, are slidable axially on the member 14, andare [held in place by a clamp ring 28 and uitable thumb screw tighteningmeans 29 or the like. The force to spring the fingers outward isadjustable by moving the clamp 28 closer to or farther away from the end18 of the member 14.

The effect of these fingers is to retard the exit of the tow from thejet and cause a temporary pile-up of a mass of dis-oriented filamentsthrough which the exhaust air from the jet must pass. This serves twofunctions. First, the kinetic energy of the exhaust air causes somefurther debundlizing of the tow filaments, promoting better blooming ofthe tow. Secondly, the exhaust air is highly filtered by the tow bundleat this point so that any addenda not previously deposited anddistributed on the tow filaments is now deposited and distributed. Thus,the need for a hood and exhaust system to remove addenda from theexhaust air is eliminated.

Reference is now made to FIG. 3 which, as indicated above, comprises analternate embodiment which may be used when it is desired to reduce theinlet diameter of the yarn entrance to the jet device. Such structure isgenerally similar to that part of the structure of FIG. 2 which it isconstructed to replace. That is, flange portion 112 would be adapted toscrew into housing 10 as does part 12. The tube portion 111 iscomparable to 11 and terminates in taper 119 of the order of, forexample, 60. The insert 117, which reduces the diameter of passageway116, would be of ceramic as the commercially obtainable materialAl-Si-Mag. Depending on the size of 117 the entrance diameter at thezone of yarn entry of, for example, one third to one fifth of the largerdiameter of 116.

If it is not desired to substitute parts as just described,alternatively as shown in FIG. 2, member 11 is threaded at 17 and a capmay be screwed on at 17 containing a ceramic insert which reduces thediameter of passage way 16.

Referring now to FIG. 4, there is shown a modification of the basiccircular device described in FIG. 2 whereby the plasticizer or likematerial may be incorporated on the tow as the tow passes through thejet. In further detail, referring to FIG. 4, the air supply line 30 tothe circular jet 6 has connected in series along its length a pressureregulator 31 and a liquid atomizing unit 32. After leaving the atomizerunit 32 the air line is branched at 33 to provide as many smaller airsupply connections as required by the jet shell 10. The plasticizerliquid in the form of an aerosol generated in the atomizer 32 isconveyed in the air to the jet 6 and impinges alongwith the air on thetow as it passes through the jet orifice plate. Several suitable meansare commercially available for generating the aerosol from theplasticizer, such as the air line lubricators made by the AlemiteCompany, of Chicago, Illinois, and it is not desired to be restricted toany particular type of aerosol generator.

Reference is now made to FIG. 5 wherein there is shown another typemodification of the circular jet whereby the plasticizer may beintroduced directly int-o the jet and onto the tow being processedtherein. A plurality of metering gear pumps 36, 36 and 36 are connectedto a supply tank 35 of plasticizer liquid. The down-stream side of eachpump is connected through pipe lines 37", 37', 37 respectively to acapillary tube probe having a small opening at the entrance end. One ormore of these probes 38 and 39 are positioned in the exit flare of theventuri member 14. One or more other probes 40 are located in the towentrance tube 11 and discharge near the orifice plate 13. As theplasticizer emerges from these probes it is distributed by the highvelocity jet air onto the tow filaments.

Consideration will now be directed to FIG. 6 which figure in certainrespects corresponds with FIG. 2 and represents the preferred apparatusembodiment of the instant invention. In referring to FIG. 6, twometering gear pumps 56 and 56 are connected to a supply tank 55 ofplasticizer. The output of these pumps is connected by flexible hose ortubing 50 and 50 to slit tube applicators 51 and 51. The tubeapplicators are stainless tubing having a narrow 0.01 to 0.06 slit cutlongitudinally along one side. The tubes are sealed at each end by endplates. One end plate may be rovided with a threaded connection to theflexible tubing 50 and 50'. The slits may be covered with thin feltand/or a fine mesh screen to help evenly distribute the flow of theplasticizer along the length of the slits. The hollow tube applicatorsare rigidly fastened to an arm 62 pivoted about the axis 63. At one endof the arm 62 the piston rod of an air cylinder 64 or solenoid isconnected with a hinge pin. The cylinder is anchored to the machineframe by a hinge pin at 65. The slot tube applicators are so mountedthat one slot faces generally downward and the other generally upward.The tow 71 passes under the downward facing slot 51 and over the upwardfacing slot 51', snubbing 5 to 30 on each slot tube. As the tow, fedthrough the nip of feed roll 4, passes under and over the slot tubes acontrolled amount of plasticizer is metered onto the tow. The aircylinder or solenoid 64 is coordinated with the start-stop means of thetow blooming apparatus to rotate the slot tubes counterclockwise out ofcontact with the tow when the machine is stopped and clockwise intocontact as the machine is started. This prevents wicking of too muchplasticizer onto spots on the tow when the machine is at rest. The towpasses over the straight tube applicators as a flat ribbon about 2 to 6wide and as it enters the jet 75 is compacted into a cylindrical form.

Thus, although every filament may not have received an application ofplasticizer from the applicators, any local point in the cross-sectionof the tow has filaments that did receive plasticizer. The amount ofplasticizer on these filaments is in general in excess of that requiredto bond the filaments together adequately. When the tow is subjected tothe hi h velocity explosive blast of air in the jet orifice plate 13(FIG. 3) and venturi tube 14, the excess plasticizer on these filamentsis blown off and impinges on the filaments that did not pick upplasticizer in passing over the applicator slots.

Thus, an aerosol of plasticizer is generated within the jet and anessentially completely uniform plasticizer distribution is achieved onall filaments in the tow by the time it emerges from the jet. The largemass of bloomed filaments retarded by the spring fingers 26, 26, etc.(FIG. 2) at the exit of the venturi tube 14 insures that only aninsignificant amount or no plasticizer will escape to the atmosphere.This is the result of the fact that, while the mass of emergingfilaments not only acts as a highly efiicient filter medium for theplasticizer, the exhaust air from the jet is so retarded and slowed downas it emerges from the mass of bloomed filaments that it no longer hassufficient velocity energy to blow off and remove plasticizer from thesurface of the bloomed filaments. Without the presence of the retardingspring fingers 26, 26, the filter mass would not be formed at the exitof the jet and poorer distribution of the plasticizer or other addendawould ensue as well as excessive losses of addenda to the atmosphere.However, in the present invention the processed tow 72 (FIG. 6) is wellbloomed and plasticized.

An understanding of the functioning of the apparatus parts disclosed inthe several figures is already apparent to a substantial extent from thepreceding description. However, a further understanding of the apparatusfunctioning will be had from a consideration of the following specificexample.

Example I Filter rods were made by the round jet device of thisinvention using the general apparatus setup of FIG, 2 and theplasticizer application apparatus of FIG. 4 and using 37,000 denier towcontaining about 23,200 filaments having an average size of 1.6 denier.For comparison, filter rods were made of the same tow using the slotventuri apparatus and method of Dyer et al. application Serial No.736,900. Also, a comparison was made with the tension blooming method ofthe prior art with a 72,000 denier, 2.0 denier per filament tow. Thephysical characteristics of the filter rods and the processing commentswere as follows:

Present gi Slot Tension Circular Venturi Blooming Venturi Total denier37, 000 37, 000 72, 000 Denier/filament... 1. 6 1. 6 2. 0 Crimps/inch16. 0 16. 0 17. 0 Weight of mm. rod, grams 0. 63 0.670 0.87 Pressuredrop of 90 mm. rod, 15.4 16.8 13. 3 Rod hardness 10. 1 8. 8 8.9 Pressuredrop of 15 m 2. 94 3. O7 2. 4 Tar removal, percent 42. 4 43. 8 34.0 .Tetair consumption, CFM free air 43 4 None Rod test designation 1 CLY 4 ARK1 AXM With the circular jet of the present invention no difficulty wasencountered with twisted tow, the air consumption was reduced about 60%,only one jet and two sets of rolls instead of three were required, andthe need for spray booths and exhaust system were eliminated. Ascompared to tension bloomed filter processing, the tow was less damagedand the weight of filter material was reduced about 25% based on rodweight while tar removal was increased.

Therefore, it is apparent from the foregoing that filters of equivalentproperties which require less material can be made using the apparatusof the present invention. Further, the size of the tow required toaccomplish this may be considerably smaller than that used in themechanical method of the prior art and this feature possesses someadditional advantages.

In carrying out the above, any of the usually used plasticizers may beemployed. That is, plasticizers such as triacetin, tripropionin, etc.may be employed. The exact addenda incorporated is not a limitation onthe instant invention and will depend to some extent on thecharacteristics of the particular tow which is being processed in theapparatus and the type of rod which it is desired to produce.

In the instance of the type of filaments which are not susceptible toplasticization, the addenda applied to the crimped filaments maycomprise a liquid monomer which will serve to bond the filaments atsuitable points, areas or zones as the filaments pass through subsequentfilter forming steps.

The amount of air pressure applied to the circular jet may and is foreconomical reasons usually kept to a reasonably low value. However, ifdesired, the pressure may be extended up to 90 psi.

It is believed apparent from the foregoing that we have provided asimplified apparatus combination for the manufacture of rods frombundles of filaments particularly filter tow. It is thought apparentfrom the foregoing description that it may be noted because of theelimination of the need for rolls, spray booths and the like equipmentthat certain apparatus savings may be secured.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

1. An apparatus arrangement for converting a bundle of filaments into arod-like element comprising feed rolls for withdrawing the bundle offilaments from a supply thereof, means in series with the feed rolls forapplying addenda to the filaments and for blowing the filamentsincluding a circular air jet adapted to subject the filaments torelatively streamline air flow in series direction, spring fingerfilament retarding means between the exit from the jet and further rollsin series, said latter rolls being adapted to withdraw the processedfilaments and supply the filaments to filter element forming andwrapping means in series.

2. An apparatus in accordance with claim 1 wherein the means in seriesincludes a device for applying addenda on one side and then on the otherside of said filaments.

3. A device adapted for blowing the filaments as set forth in claim 1,said device being comprised of a tube entrance element and a tube-typeexit member, an orifice plate positioned between the aforesaid members,said orifice plate and adjacent portions of said tube members beingenclosed in a housing whereby there is provided a chamber adapted toreceive a gaseous fluid supplied thereto so that said fluid flowsthrough the orifice plate and discharges through the exit member, saiddevice being further characterized in that the exit member has attachedto the end thereof spring means whereby the exit of the tow from thedevice may be retarded.

4. A device in accordance with claim 3 wherein the chamber is connectedwith an aerosol generating means.

5. A device in accordance with claim 3 wherein the inlet tube and outlettube have associated therewith conduits which are connected with asource of plasticizer whereby said plasticizer may be injected into saidtubes.

6. A device in accordance with claim 3 wherein means are provided onentrance member so that the diameter is reduced one third to one fifththe diameter of the passage beyond the entrance.

7. A jet device for the treatment of a material passing therethrough, anentrance element, an exit member, an orifice between said entranceelement and said exit memher, a housing enclosing said parts, and aplurality of spring retarding means arranged'to cooperate with said exitmember to reduce the speed of the material leaving said exit member.

' 8. A device in accordance with claim 7 wherein means are provided forreducing the diameter of the entrance of said entrance member.

9. A device in accordance with claim 7 wherein a plurality of conduitmeans are provided for introducing addenda to within the interior of thejet.

References Cited by the Examiner UNITED STATES PATENTS 2,794,480 6/ 1957Crawford et al 156441 2,924,868 2/1960 Dyer 28-1 2,982,000 5/1961Gonsalves 28-1 3,055,251 10/1961 Hallden et al. 28-1 EARL M. BERGERT,Primary Examiner.

R. C. CARLSON, J. P. MELOCHE, Assistant Examiners.

1. AN APPARATUS ARRANGEMENT FOR CONVERTING A BUNDLE OF FILAMENTS INTO ARID-LIKE ELEMENT COMPRISING FEED ROLLS FOR WITHDRAWING THE BUNDLE OFFILAMENTS FROM A SUPPLY THEREOF, MEANS IN SERIES WITH THE FEED ROLLS FORAPPLYING ADDENDA TO THE FILAMENTS AND FOR BLOWING THE FILAMENTSINCLUDING A CIRCULAR AIR JET ADAPTED TO SUBJECT THE FILAMENTS TORELATIVELY STREAMLINE AIR FLOW IN SERIES DIRECTION, SPRING FINGERFILAMENT RETARDING MEANS BETWEEN THE EXIT FROM THE JET AND FURTHER ROLLSIN SERIES, SAID LATTER ROLLS BEING ADAPTED TO WITHDRAW THE PROCESSEDFILAMENTS AND SUPPLY THE FILAMENTS TO FILTER ELEMENT FORMING ANDWRAPPING MEANS IN SERIES.